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Finding the Fourth Proportional to 989.84, 1,485.05 and 331.79

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Solution

The fourth proportional to 989.84, 1,485.05 and 331.79 is: 497.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    989.84 : 1,485.05 = 331.79 : x
  2. Step 2: Convert to fraction form
    989.84/1,485.05 = 331.79/x
  3. Step 3: Cross multiply
    989.84x = 1,485.05 × 331.79
  4. Step 4: Simplify right side
    989.84x = 492,715.66
  5. Step 5: Solve for x
    x = 492,715.66/989.84
  6. Step 6: Final answer
    x = 497.78

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.